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