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