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