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