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