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