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