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