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