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)(11,14)(12,19)(13,15)(16,21)(17,23)(18,24)(20,22)(25,26,32,38)(27,35,29,33)(28,37,31,34)(30,36,40,39)(1,3,4,7)(2,5,6,8)(9,11,13,17)(10,14,15,23)(12,20,21,18)(16,24,19,22)(25,27,32,29)(26,33,38,35)(28,39,31,36)(30,37,40,34)(1,2)(3,5)(4,6)(7,8)(10,15)(11,17)(16,19)(18,20)(25,28,32,31)(26,34,38,37)(27,39,29,36)(30,35,40,33)(9,10)(11,14)(12,16)(13,15)(17,23)(18,22)(19,21)(20,24)(25,29,32,27)(26,35,38,33)(28,39,31,36)(30,37,40,34)(1,3)(2,5)(4,7)(6,8)(9,11)(10,14)(12,18)(13,17)(15,23)(16,22)(19,24)(20,21)(25,30,32,40)(26,36,38,39)(27,34,29,37)(28,33,31,35)(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,18)(13,21)(14,22)(15,19)(17,20)(23,24)(25,31,32,28)(26,37,38,34)(27,39,29,36)(30,35,40,33)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.