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