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