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