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)(14,28)(15,20)(17,26)(18,22)(21,34)(23,33)(25,31)(27,35)(29,32)(30,36)(37,39)(38,40) involution — undirected(1,3,5,4)(2,6,7,8)(9,11)(10,16)(12,25)(13,22)(14,29)(15,23)(17,34)(18,19)(20,33)(21,26)(24,31)(27,37)(28,32)(30,38)(35,39)(36,40)(1,4,5,3)(2,6,7,8)(9,12)(10,17)(11,21)(13,26)(14,30)(15,27)(16,31)(18,34)(19,35)(20,36)(22,37)(23,38)(24,28)(25,29)(32,40)(33,39)(9,11)(10,18)(12,21)(13,22)(14,29)(15,23)(16,28)(17,34)(19,33)(20,32)(24,31)(25,30)(26,37)(27,38)(35,39)(36,40) involution — undirected(2,7)(6,8)(9,13,15,14)(10,19,20,28)(11,22,23,29)(12,26,27,30)(16,18,33,32)(17,35,36,24)(21,37,38,25)(31,34,39,40)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.