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