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