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)(11,13)(12,15)(14,20)(16,23)(17,18)(19,22)(21,24)(25,26,31,28)(27,34,33,30)(29,32,38,36)(35,40,39,37)(2,3)(6,7)(9,11)(10,13)(12,18)(14,19)(15,17)(16,21)(20,22)(23,24)(25,26,31,28)(27,30,33,34)(29,36,38,32)(35,40,39,37)(1,3,5,2)(4,7,8,6)(10,12)(11,17)(16,20)(19,24)(25,27)(26,30)(28,34)(29,35)(31,33)(32,37)(36,40)(38,39)(1,4,5,8)(2,6,3,7)(9,12,15,10)(11,18,17,13)(14,20,23,16)(19,22,24,21)(25,28,31,26)(27,34,33,30)(29,36,38,32)(35,40,39,37)(9,13,15,18)(10,11,12,17)(14,22,23,21)(16,24,20,19)(25,29)(26,32)(27,35)(28,36)(30,37)(31,38)(33,39)(34,40)(9,14,15,23)(10,16,12,20)(11,19,17,24)(13,21,18,22)(25,30,31,34)(26,33,28,27)(29,37,38,40)(32,39,36,35)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.