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