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