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