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