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