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