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