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