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