One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,8)(6,7)(9,10,14,16)(11,15,18,12)(13,21,22,17)(19,20,24,23)(25,26,31,35)(27,32,36,30)(28,33,37,40)(29,34,38,39)(1,3)(2,6)(4,8)(5,7)(9,11)(10,15)(12,16)(13,19)(14,18)(17,23)(20,21)(22,24)(25,27,31,36)(26,32,35,30)(28,38,37,29)(33,39,40,34)(1,2)(3,6)(4,7)(5,8)(10,16)(11,18)(13,22)(20,23)(27,36)(29,38)(30,32)(34,39) involution — undirected(1,4,5,6)(2,7,8,3)(9,12)(10,11)(13,20)(14,15)(16,18)(17,19)(21,24)(22,23)(25,28)(26,33)(27,29)(30,39)(31,37)(32,34)(35,40)(36,38)(1,4)(2,3)(5,6)(7,8)(9,11)(10,15)(12,16)(13,19)(14,18)(17,23)(20,21)(22,24)(25,29)(26,34)(27,37)(28,36)(30,33)(31,38)(32,40)(35,39) involution — undirected(1,3)(2,4)(5,7)(6,8)(9,13,14,22)(10,17,16,21)(11,19,18,24)(12,20,15,23)(25,30)(26,27)(28,39)(29,33)(31,32)(34,37)(35,36)(38,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.