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