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