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