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