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