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