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