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