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