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