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