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