One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,4)(3,7,8,6)(10,15)(11,16)(17,22)(18,23)(25,26,31,34)(27,30,33,39)(28,29,32,38)(35,36,37,40)(1,3)(2,6)(4,7)(5,8)(9,10,14,15)(11,12,16,20)(13,17,21,22)(18,19,23,24)(25,27)(26,30)(28,35)(29,36)(31,33)(32,37)(34,39)(38,40)(2,4)(6,7)(13,21)(17,22)(18,23)(19,24)(27,33)(30,39)(35,37)(36,40) involution — undirected(1,3,5,8)(2,6,4,7)(9,11)(10,12)(13,18)(14,16)(15,20)(17,19)(21,23)(22,24)(25,28)(26,29)(27,35)(30,36)(31,32)(33,37)(34,38)(39,40)(1,3)(2,6)(4,7)(5,8)(9,12)(10,16)(11,15)(13,19)(14,20)(17,23)(18,22)(21,24)(25,29)(26,32)(27,36)(28,34)(30,37)(31,38)(33,40)(35,39) involution — undirected(1,4,5,2)(3,7,8,6)(9,13)(10,17)(11,18)(12,19)(14,21)(15,22)(16,23)(20,24)(25,30,31,39)(26,33,34,27)(28,36,32,40)(29,37,38,35)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.