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