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