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