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