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